The Candy Dungeon is the Candy Kingdom's dungeon that is used to detain prisoners.
In "Too Young," Earl of Lemongrab was fond of sending Candy Kingdom citizens to the dungeon for periods ranging from three hours to one million years for a variety of infractions, including the prank where Princess Bubblegum and Finn put hot sauce in his food.
In "Apple Wedding," Princess Bubblegum imprisons all the attendants of Tree Trunks' wedding in an act of revenge against the King of Ooo, whom she considers a charlatan. Undaunted, Tree Trunks insists they continue the ceremony, but the King of Ooo manages to chew through the candy steel bars and escape, leaving Tree Trunks to officiate her own wedding. Princess Bubblegum observes this via closed circuit television and releases the prisoners in remission.
The dungeon has several levels with detention cells. The upper level is made of stone and wood and has a row of multiple cells. There are also small, wooden cages hanging from the ceiling. The lower level is made mostly from wood and dirt, with stones scattered throughout. The wood has the appearance of roots which have grown into place and are used as part of the structures in the room (such as the Shelf of Penitence). There is a single cell in the center of this level, which has the Occulus of Rehabilitation in its ceiling. Both levels are dark with no visible signs of lighting other than natural light. There are also secret entrances throughout the dungeon.